Process of refining metals



Patented July 7, 1 931 I UNITED STATES- PATENT OFFICE WALTER 0. SMITH, OF MOYLAN, PENNSYLVANIA, ASSIGNOR TO ALLIED PROCESS COR PORATION, OF NEW YORK, N. Y.', A CORPORATION OF NEW YORK PROGESS OF REFINING METALS No Drawing.

' This invention relates to a process for the deoxidization and degasification of copper, copper alloys such as brasses and bronzes and other metals and alloys such as zinc and its alloys, nickel, cupro-nickel alloys, iron, steel, and ferrous alloys such as rustless iron, in order to prepare the metal forthe production of sound ingots and castings and articles deofthe agent left in the treated metal, they.

. have a marked delete'riousefl'ect upon some of the more important characteristics of the metal, such as electrical conductivity.

Lithium, as I have disclosed in my copend ing application Serial No. 225,845, filed October 12, 1927, is a superior deoxidizing and degasifying agent for metals, particularly copper and its allo s in that it accom lishes the desired degasi cation while reat y improving the ductility, malleabillty, tensile strength and elongation of the metal, and

when present in thefinished metal in sufficiently small amounts does. not appreciably reduce its electrical conductivity. Lithium, however, is relatively expensive and an object of my present invention is to secure all of the advantages incident to the use of lithium as the deoxidizing agent, while at the same time limiting the quantity of lithium required to be used and thereby reducing the cost of the operation. ThisI accomplish by 7 using a small amount of lithium in conjunction' with the use of a less expensive agent such as phosphorus. Y

Lithium, as I have found, is n'ot pable of deoxidizing but also apparently is capable of denitrifying, desulfurizin and dephosphorizing the metal, andthere ore, is

capable of completing the deoxidization'if it Application flled June 21,

unconsumed and alloyed with the cop only ca- 1929. Serial No. 372,797.

is not completed by the action of the less expensive agent, and in addition is capable of destroying the deleterious effects produced by the less expensive agent so that aresult equal to that produced by the action of lithium alone is accomplished by the use of only a small amount of lithium in conjunction witha less expensive agent. lVhether the lithium acts solely to complete the deoxidation or to remove traces of the other deoxidizing agent employed, and the presence of which has a deleterious efiect upon the metal, or both has not been determined. A preferred procedure, however, is to use enough of the deoxidizing agent such as phosphorus or silicon to accomplish a complete deoxidization in accordance with wellknown practice and then to treat the metal with a very small-amount of lithium. As stated, a small amount of lithium left in the metal is not detrimental. My invention, therefore, contemplates the partial or complete deoxidization and degasi? cation of metals'in any well-known way in conjunction with a treatment of the metal with lithium as described in my copending application above referred to. or example copper is treated first in the well-known way with phosphor-copper and then with lithium as such or in the form of an alloy thereof,

such as a copper-lithium alloy. The quantity of lithium required'will vary widely depending upon'the character or purity of the metal treated and the quantity of phosphor-copper used. The quantity should be adjusted so that as little as possible of lithiu'mremains r. The quantity r uired cannot readily be determined by ana ysis but is best determined by tests upon small batches of the metal under treatment, using different amounts until the desired effect is obtained. It may be said that additions of lithium in uantities of the order o1f)l.O001% to .05% have 11 found to besuita e As will be understood from the tenor of the the copper at the customary copper refining temperature, that is, from about 1100 C. to about 1250 C. c

ll claim:

1. In the process of producing sound cast: ings of copper the steps which consist in first at least partially degasifying and deoxidizing the molten metal by the addition thereto of an agent other than lithium and thereafter adding to the molten metal lithium in quantity of from about 0.0001% to about 0.05% at the customary copper-refining tem- 10 perature'of from about 1100 C. to-about 2. In the process of producing sound cast-. ings of copper the steps which consist in first at least partially degasifying and deoxil dizing the molten metal by the addition thereto of an agent consisting essentially of phosphorus and thereafter adding to the molten metal lithium in quantity of from about 0.0001% to about 0.05% at the customary copper-refining temperature of from about v 1100? C. to about 1250 C. v

ln testimony whereof; I affix my signature.

WALTER C. SMITH. 

